1. Field of the Invention
The present invention is related in general to a hopper car for carrying bulk materials and more particularly to a hopper car having an increased volume for carrying the bulk materials.
2. Description of Related Art
Hopper cars are commonly used to transport and sometimes store bulk materials. Hopper cars include one or more hoppers which allow the bulk materials to be discharged from the car bottom. Each hopper has a discharge opening at its bottom in order to discharge the cargo. The cargo may be discharged into a large pit, or into chutes corresponding with the hopper openings. A variety of door and gate assemblies in conjunction with various opening mechanisms are used to open and close hopper car discharge openings.
There are maximum exterior dimensions to which hopper cars must conform. For example, the Association of American Railroads (AAR) establishes maximum clearance dimensions for all railcars including hopper cars. Also, the Federal Highway Administration and state agencies establish maximum width and height requirements for freight trucks. To effectively discharge all bulk materials residing in a hopper car, the lower portion of the hopper walls are angled. The desired angle depends on what type of material the hopper car is transporting. Moreover, discharge openings on a hopper car are generally sized to fit traditional gate sizes. Increasing the number of discharge openings on a given hopper car increases car construction expenses. It is therefore desirable to maximize volumetric capacity of a hopper car within the specified dimensional requirements while minimizing car construction expense.